/* Linuxthreads - a simple clone()-based implementation of Posix */ /* threads for Linux. */ /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */ /* */ /* This program is free software; you can redistribute it and/or */ /* modify it under the terms of the GNU Library General Public License */ /* as published by the Free Software Foundation; either version 2 */ /* of the License, or (at your option) any later version. */ /* */ /* This program is distributed in the hope that it will be useful, */ /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */ /* GNU Library General Public License for more details. */ #ifndef _SEMAPHORE_H #define _SEMAPHORE_H 1 #include <features.h> #include <sys/types.h> #ifdef __USE_XOPEN2K # define __need_timespec # include <time.h> #endif #ifndef _PTHREAD_DESCR_DEFINED /* Thread descriptors. Needed for `sem_t' definition. */ typedef struct _pthread_descr_struct *_pthread_descr; # define _PTHREAD_DESCR_DEFINED #endif /* System specific semaphore definition. */ typedef struct { struct _pthread_fastlock __sem_lock; int __sem_value; _pthread_descr __sem_waiting; } sem_t; /* Value returned if `sem_open' failed. */ #define SEM_FAILED ((sem_t *) 0) /* Maximum value the semaphore can have. */ #define SEM_VALUE_MAX ((int) ((~0u) >> 1)) __BEGIN_DECLS /* Initialize semaphore object SEM to VALUE. If PSHARED then share it with other processes. */ extern int sem_init (sem_t *__sem, int __pshared, unsigned int __value) __THROW; /* Free resources associated with semaphore object SEM. */ extern int sem_destroy (sem_t *__sem) __THROW; /* Open a named semaphore NAME with open flags OFLAG. */ extern sem_t *sem_open (__const char *__name, int __oflag, ...) __THROW; /* Close descriptor for named semaphore SEM. */ extern int sem_close (sem_t *__sem) __THROW; /* Remove named semaphore NAME. */ extern int sem_unlink (__const char *__name) __THROW; /* Wait for SEM being posted. This function is a cancellation point and therefore not marked with __THROW. */ extern int sem_wait (sem_t *__sem); #ifdef __USE_XOPEN2K /* Similar to `sem_wait' but wait only until ABSTIME. This function is a cancellation point and therefore not marked with __THROW. */ extern int sem_timedwait (sem_t *__restrict __sem, __const struct timespec *__restrict __abstime); #endif /* Test whether SEM is posted. */ extern int sem_trywait (sem_t *__sem) __THROW; /* Post SEM. */ extern int sem_post (sem_t *__sem) __THROW; /* Get current value of SEM and store it in *SVAL. */ extern int sem_getvalue (sem_t *__restrict __sem, int *__restrict __sval) __THROW; __END_DECLS #endif /* semaphore.h */